Apparatus and method for moving PN hypothesis in high speed searcher

Abstract

There is provided a PN (Pseudorandom Noise) hypothesis moving apparatus and method in a high speed searcher. In the PN hypothesis moving apparatus, a PN sequence generator system has a PN sequence generator for generating a PN sequence and a PN state register for storing information about a PN state. A correlation counter counts the number of correlations, and a comparator receives the output of the correlation counter, a correlation length, and a search speed, compares them, and provides a PN state saving point and a PN state loading point to the PN sequence generator system according to the comparison to change a PN hypothesis.

1. A PN (Pseudorandom Noise) hypothesis moving apparatus in a high speed searcher, for synchronizing a mobile station comprising:
 a correlation counter for counting the number of correlations; a comparator for receiving a correlation count, for comparing the correlation count with at least one parameter and for providing one of a storing command and a loading command according to the comparison to change a PN hypotheses; and 
 a PN sequence generator system for storing a PN state according to the storing command and outputting the PN state according to the loading command of the comparator to synchronize the mobilestation. 
 
   
   
     2. The PN hypothesis moving apparatus of  claim 1 , wherein the at least one parameter includes a correlation length and a search speed. 
   
   
     3. The PN hypothesis moving apparatus of  claim 2 , wherein the comparator provides the storing command indicating if the correlation length minus the search speed is equal to the correlation count, and the comparator provides the loading command if the correlation length is equal to the correlation count. 
   
   
     4. The PN hypothesis moving apparatus of  claim 1 , wherein the PN sequence generator system comprises a PN sequence generator for generating a PN sequence, and a PN state register for storing the PN state according to the storing command and outputting the stored PN state according to the loading command. 
   
   
     5. A PN hypothesis moving method in a high speed searcher, for synchronizing a mobile station comprising the steps of:
 receiving a correlation count, a correlation length, and a search speed; 
 storing information about a PN state, if the correlation count is equal to the correlation length minus the search speed; and 
 loading information about the PN state, if the correlation count is equal to the correlation length to synchronize the mobile station by changing a PN hypothesis at a PN hypothesis changing point. 
 
   
   
     6. The method of  claim 5 , further comprising the steps of:
 storing the PN state corresponding to a time point prior to the PN hypothesis changing point; and 
 loading the PN state corresponding to the time point prior to the PN hypothesis changing point during the PN hypothesis changing point.